icingaweb2/library/Icinga/Chart/SVGRenderer.php

331 lines
8.3 KiB
PHP

<?php
/* Icinga Web 2 | (c) 2013 Icinga Development Team | GPLv2+ */
namespace Icinga\Chart;
use DOMNode;
use DOMElement;
use DOMDocument;
use DOMImplementation;
use Icinga\Chart\Render\LayoutBox;
use Icinga\Chart\Render\RenderContext;
use Icinga\Chart\Primitive\Canvas;
/**
* SVG Renderer component.
*
* Creates the basic DOM tree of the SVG to use
*/
class SVGRenderer
{
const X_ASPECT_RATIO_MIN = 'xMin';
const X_ASPECT_RATIO_MID = 'xMid';
const X_ASPECT_RATIO_MAX = 'xMax';
const Y_ASPECT_RATIO_MIN = 'YMin';
const Y_ASPECT_RATIO_MID = 'YMid';
const Y_ASPECT_RATIO_MAX = 'YMax';
const ASPECT_RATIO_PAD = 'meet';
const ASPECT_RATIO_CUTOFF = 'slice';
/**
* The XML-document
*
* @var DOMDocument
*/
private $document;
/**
* The SVG-element
*
* @var DOMNode
*/
private $svg;
/**
* The description of this SVG, useful for screen readers
*
* @var string
*/
private $ariaDescription;
/**
* The title of this SVG, useful for screen readers
*
* @var string
*/
private $ariaTitle;
/**
* The aria role used by this svg element
*
* @var string
*/
private $ariaRole = 'img';
/**
* The root layer for all elements
*
* @var Canvas
*/
private $rootCanvas;
/**
* The width of this renderer
*
* @var int
*/
private $width = 100;
/**
* The height of this renderer
*
* @var int
*/
private $height = 100;
/**
* Whether the aspect ratio is preversed
*
* @var bool
*/
private $preserveAspectRatio = false;
/**
* Horizontal alignment of SVG element
*
* @var string
*/
private $xAspectRatio = self::X_ASPECT_RATIO_MID;
/**
* Vertical alignment of SVG element
*
* @var string
*/
private $yAspectRatio = self::Y_ASPECT_RATIO_MID;
/**
* Define whether aspect differences should be handled using padding (default) or cutoff
*
* @var string
*/
private $xFillMode = "meet";
/**
* Create the root document and the SVG root node
*/
private function createRootDocument()
{
$implementation = new DOMImplementation();
$docType = $implementation->createDocumentType(
'svg',
'-//W3C//DTD SVG 1.1//EN',
'http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd'
);
$this->document = $implementation->createDocument(null, null, $docType);
$this->svg = $this->createOuterBox();
$this->document->appendChild($this->svg);
}
/**
* Create the outer SVG box containing the root svg element and namespace and return it
*
* @return DOMElement The SVG root node
*/
private function createOuterBox()
{
$ctx = $this->createRenderContext();
$svg = $this->document->createElement('svg');
$svg->setAttribute('xmlns', 'http://www.w3.org/2000/svg');
$svg->setAttribute('xmlns:xlink', 'http://www.w3.org/1999/xlink');
$svg->setAttribute('role', $this->ariaRole);
$svg->setAttribute('width', '100%');
$svg->setAttribute('height', '100%');
$svg->setAttribute(
'viewBox',
sprintf(
'0 0 %s %s',
$ctx->getNrOfUnitsX(),
$ctx->getNrOfUnitsY()
)
);
if ($this->preserveAspectRatio) {
$svg->setAttribute(
'preserveAspectRatio',
sprintf(
'%s%s %s',
$this->xAspectRatio,
$this->yAspectRatio,
$this->xFillMode
)
);
}
return $svg;
}
/**
* Add aria title and description
*
* Adds an aria title and desc element to the given SVG node, which are used to describe this SVG by accessibility
* tools such as screen readers.
*
* @param DOMNode $svg The SVG DOMNode to which the aria attributes should be attached
* @param $title The title text
* @param $description The description text
*/
private function addAriaDescription(DOMNode $svg, $titleText, $descriptionText)
{
$doc = $svg->ownerDocument;
$titleId = $descId = '';
if (isset($this->ariaTitle)) {
$titleId = 'aria-title-' . $this->stripNonAlphanumeric($titleText);
$title = $doc->createElement('title');
$title->setAttribute('id', $titleId);
$title->appendChild($doc->createTextNode($titleText));
$svg->appendChild($title);
}
if (isset($this->ariaDescription)) {
$descId = 'aria-desc-' . $this->stripNonAlphanumeric($descriptionText);
$desc = $doc->createElement('desc');
$desc->setAttribute('id', $descId);
$desc->appendChild($doc->createTextNode($descriptionText));
$svg->appendChild($desc);
}
$svg->setAttribute('aria-labelledby', join(' ', array($titleId, $descId)));
}
/**
* Initialises the XML-document, SVG-element and this figure's root canvas
*
* @param int $width The width ratio
* @param int $height The height ratio
*/
public function __construct($width, $height)
{
$this->width = $width;
$this->height = $height;
$this->rootCanvas = new Canvas('root', new LayoutBox(0, 0));
}
/**
* Render the SVG-document
*
* @return string The resulting XML structure
*/
public function render()
{
$this->createRootDocument();
$ctx = $this->createRenderContext();
$this->addAriaDescription($this->svg, $this->ariaTitle, $this->ariaDescription);
$this->svg->appendChild($this->rootCanvas->toSvg($ctx));
$this->document->formatOutput = true;
return $this->document->saveXML();
}
/**
* Create a render context that will be used for rendering elements
*
* @return RenderContext The created RenderContext instance
*/
public function createRenderContext()
{
return new RenderContext($this->document, $this->width, $this->height);
}
/**
* Return the root canvas of this rendered
*
* @return Canvas The canvas that will be the uppermost element in this figure
*/
public function getCanvas()
{
return $this->rootCanvas;
}
/**
* Preserve the aspect ratio of the rendered object
*
* Do not deform the content of the SVG when the aspect ratio of the viewBox
* differs from the aspect ratio of the SVG element, but add padding or cutoff
* instead
*
* @param bool $preserve Whether the aspect ratio should be preserved
*/
public function preserveAspectRatio($preserve = true)
{
$this->preserveAspectRatio = $preserve;
}
/**
* Change the horizontal alignment of the SVG element
*
* Change the horizontal alignment of the svg, when preserveAspectRatio is used and
* padding is present. Defaults to
*/
public function setXAspectRatioAlignment($alignment)
{
$this->xAspectRatio = $alignment;
}
/**
* Change the vertical alignment of the SVG element
*
* Change the vertical alignment of the svg, when preserveAspectRatio is used and
* padding is present.
*/
public function setYAspectRatioAlignment($alignment)
{
$this->yAspectRatio = $alignment;
}
/**
* Set the aria description, that is used as a title for this SVG in screen readers
*
* @param $text
*/
public function setAriaTitle($text)
{
$this->ariaTitle = $text;
}
/**
* Set the aria description, that is used to describe this SVG in screen readers
*
* @param $text
*/
public function setAriaDescription($text)
{
$this->ariaDescription = $text;
}
/**
* Set the aria role, that is used to describe the purpose of this SVG in screen readers
*
* @param $text
*/
public function setAriaRole($text)
{
$this->ariaRole = $text;
}
private function stripNonAlphanumeric($str)
{
return preg_replace('/[^A-Za-z]+/', '', $str);
}
}